The Global Positioning System (GPS) has been known as highly accurate positioning technology. The GPS is the positioning technology that utilizes radio waves transmitted from GPS satellites. In the GPS, a positioning error becomes large for an indoor environment where a number of visible satellites that can be utilized for positioning is small. For example, in an indoor environment, it is possible that the positioning error becomes several hundred meters. In addition, the positioning itself may become impossible.
In order to realize highly accurate positioning in an indoor environment as well as in an outdoor environment, positioning technology has been focused on such that it utilizes a wireless local area network (WLAN) (hereinafter, referred to as the “WLAN positioning”).
In the WLAN positioning, a position is estimated by utilizing radio wave information from a WLAN access point. In the WLAN positioning, since WLAN access points are not connected, the positioning can be performed with respect to all the WLAN access points whose radio wave information can be utilized.